Mechanism for adjusting the ink supply zone in a two drum stencil duplicator

ABSTRACT

A two-drum stencil duplicator comprising an adjusting mechanism for positioning an ink zone adjustment member to supply ink in a selected zone in the transverse direction of the stencil. The adjusting mechanism comprises a controllable coupling providing a drive connection between the zone adjustment member and a continuously rotating drive shaft as well as a number of individual operating members equal to the number of selectable ink supply zones for selectively actuating said coupling to interrupt the drive connection when the zone adjustment member reaches the position corresponding to a selected ink supply zone.

ite States atent 11 1 Zeuthen et a1.

1451 Apr. 16, 1974 Assignee:

MECHANISM FOR ADJUSTING THE INK SUPPLY ZONE IN A TWO DRUM STENCIL DUPLICATOR Inventors: Karl Gustav Zeuthen, Gentofte;

' Sven Erik Larsson, Rodovre, both of Denmark Zeuthen & Aagaard A/S, Glostrup, Denmark Filed: Mar. 31, 1972 Appl. No.: 240,125

Foreign Application Priority Data Apr. 16, 1971 Denmark 1830/71 U.S. Cl...; 101/119, 101/122, 101/365, 101/366, 192/33 'Int. Cl B411 13/08, B41f 31/02 Field of Search 101/132, 132.5, 229, 366, 'lO-l/l 19-122, 365; 251/319; 192/24, 25, 33

References Cited UNITED STATES PATENTS 1/1964 Oderman et a1. 101/365 5/1873 Bingham 101/229 x 2,183,568 12/1939 Huck 101/366 x 2,225,421 12/1940 Marchev 101/132 x 2,893,318 7/1959 Kreher 101/366 2,992,608 7/1961 Williams.... 101 13'25 3,166,012 1/1965 l-lantschom 101/229 x 3,306,195 2/1967 Cutri 101/132.5

Primary Examiner-Robert E. Pulfrey Assistant ExaminerPaul T. Sewell Attorney, Agent, or Firm-Stevens, Davis, Miller and Mosher [5 7] ABSTRACT A two-drum stencil duplicator comprising an adjusting mechanism for positioning an ink zone adjustment member to supply ink in a selected zone in the transverse direction of the stencil. The adjusting mechanism comprises a controllable coupling providing a drive connection between the zone adjustment membet and a continuously rotating drive shaft as well as a number of individual operating members equal to the number, of selectable ink supply zones for selectively actuating said coupling to interrupt the drive connection when the zone adjustment member reaches the position corresponding to a selected ink supply zone.

5 Claims, 12 Drawing Figures PATENTEDAPR 1 I974 SHEET 2 [1F 6 PATETED APR 1 6 I974 SHEEI 5 BF 6 PATETEUAPR 16 1914 sum 8 or IAU MECHANISM FOR ADJUSTING THE INK SUPPLY ZONE IN A TWO DRUM STENCIL DUPLICATOR The present invention relates to two-roller duplicators and, in particular, to a mechanism for adjusting the ink supply zone in such duplicators.

BACKGROUND OF THE INVENTION In two-drum stencil duplicators such as described, for example, in US. Pat. No. 2,893,318 to R. Kreher, sheets of paper are printed by means of a stencil which is usually supported by an endless ink cloth trained around two drums extending in parallel relationship one above the other. Ink is usually supplied to the ink cloth via the lower drum by means of an ink supply unit comprising an ink tube extending parallel to the lower drum at a short distance therefrom, said tube being provided with a number of ink discharge apertures facing the lower drum and being uniformly distributed in the axial direction of the ink tube. In order to adjust the ink supply to different zones in the transverse direction of the ink cloth and stencil, the ink tube usually comprises a movable zone adjustment member, e.g. in the form of a rotatable inner tube, by means of which ink supplied, for example, from an ink cartridge by means of an ink pump unit may be discharged through the total number of ink discharge apertures or a smaller number of apertures covering only a section such as an outer section or a central section in the axial direction of the ink tube.

In all prior art duplicators of the type mentioned this.

zone adjustment is performed manually by means of an operating member, e.g. in the form of a hand wheel, which positions the zone adjustment member via asuitable gearing in accordance with the desired ink supply zone.

However, since the inner tube or zone adjustment member in order to'secure sufficient ink,.sealing will necessarily have to fit tightly in the ink tube, manual turning of such a hand wheel will require a considerable force, so that the zone adjustmentbecomes a diffi cult and slow operation which often causes algreat' delay'of the duplicating work and entails a'conside'rable waste. This applies particularly to tli'eafter-adjustment which it is usually necessary to perform after some times duplication to'obtain prints witha' satisfactorily uniform inking.

SUMMARY OF THE INVENTION According to the invention there is provided'a stencil duplicator comprising a lower drum and an upper drum mounted rotatably in parallel relationship, drive means for said drums including a continuously rotating drive shaft, an endless ink cloth trained around said drums to support a stencil, means for supplying ink to said ink cloth and including an ink tube extending parallel to the lower drum at a short distance therefrom, said ink tube being provided with a number of ink discharge apertures facing the lowerdrum, a zone adjustment mem-,

ber movably arranged in said ink tube to adjust the ink supply through said discharge apertures to anyone of a number of different zones in the transverse direction of said ink cloth and an adjusting mechanism toposition said zone adjustment member, said adjusting mechanism comprising a number of individual operating members equal to the number of ink supply zones and a coupling selectively actuatable by each of said operating members to provide a drive connection between said drive shaft and said zone adjustment member and interrupt said drive connection when the zone adjustment member reaches the position corresponding to the ink supply zone associated with said operating member. I

Since the necessary operation for the zone operation now consist only in actuating a certain operating member which is associated with the particular ink supply zone and which is not to influence the zone adjustment member directly, but actuates a rapidly acting coupling the operation is facilitated consideably, so that it becomes essentially easier and quicker to work with the duplicator, it being possible hereby almost completely to avoid waste.

Moreover, in a duplicator according to the invention it is possible without difficulty, to mount the individual operating members for the various ink discharge zones in the most expedient place in the duplicator and in connection with this provide the duplicator with a direct indication for the particular ink supply zone corresponding to each operating member.

The employment of the selectively actuatable coupling furthermore entailsa great flexibility in the construction, it being possible to use the adjusting mechanism in connection with an ink tube of the known design'mentioned above with a rotatable zone adjustment member as well as with an ink supply unit where the movement of the adjustment member is not a turning,

but an axial displacement.

BRIEF DESCRIPTION OF THE DRAWINGS.

The invention will be described in greater detail with reference to the drawing in which:

FIG. 1 is aperspective view of an embodiment of a two stencil duplicator according to a zone adjusting mechanism FIG. 2 shows alongitudinal'section through an ink tube unit'in the duplicator shown inFIG. 1' and a selectively actuatable coupling connected therewith FIG 3 is a cross-sectional view along the line III,III inFIG. 2;

FIG. 4 is an unfolded view of an inner ink duct tube inthe ink tube in FIG. 2;

FIG; 5 is an exploded perspective view of the coupling shown in FIG; 2; I

FIG 6 is aperspective view of a coupling disc in the coupling in FIG. 5;

FIG. 7 is a more detailed illustration of the cooperation between the coupling'in-FIG. Sand an operating memberin the adjusting mechanism according to the inventionj FIG. 8 shows a modification of the zone adjusting mechanism in FIG. 1;

FIG.' 9 shows a longitudinal section through another embodiment of an ink tube for use in the duplicator in FIG. 1;

FIG. 10 is a cross-sectional 'view along the line XX in FIG. 9;

the invention with FIG. 11 is an unfolded view of an inner ink duct tube in the ink tube in FIG. 9; and

FIG. 12 shows part of a selectively actuatable coupling for use in connection with the ink tube shown in FIGS. 9-11.

DETAILED DESCRIPTION.

ably, while 5 designates a top plate. The ink supply to an ink cloth not shown stretched across'the rollers 3 and 4 is effected by means of an ink tube 6 which is mounted parallel to the lower drum 3 and spaced slightly therefrom, i.e. 0.5 mm, and which in the,duplicator shown is an ink tube which as a whole is designated by the reference numeral 6. In the end located closest to the side wall 2 the ink tube connected via a link 7 to an ink' supply tube 8 which is connected to an ink pump, not shown in the figure, which e.g. may be arranged for discharging ink from an ink' cartridge to the ink tube by the actuation of an operating member intended for this purpose at this member may, as shown, have the form ofa push button 9 which actuates the ink pump via an actuating mechanism not further shown. Tube 6 is furthermore, as will be dealt with in the following, so arranged that the discharge of ink can be adjusted so as to take place within a predetermined zone in the width direction of the duplicator.

In order to adjust the ink discharge to a predetermined zone in the transverse direction of the ink cloth, the ink tube 6 contains, as shown in FIG. 2, an outer tube 10 which along a generatrix facing the lower drum 3 and is provided with a number of ink discharge apertures 11, an inner ink duct tube 12 which is mounted co-axially in the outer tube 10 and is connected via the connecting branch 7 to the ink supply tube 8, and a zone adjustment tube 13 which is mounted rotatably in the ink duct tube 12. At the ends of the outer tube 10, the clearance between this tube and the ink duct tube 12 is sealed by means of sealing bushes 14 and 15.

In order to provide flow passages for the ink from the interior of the zone adjustment tube 13 to the clearance between the tubes 10 and 12 the ink duct tube 12 is provided with four ink discharge apertures .16, 17, 18 and 19, of which apertures 16, 17 and 18 are located along the same generatrix of the tube that is in the end located closest to the side wall 1, at the middle of the tube and in the end located closest to the side wall 2, respectively. Aperture 19 is located diametrically opposite the aperture 17, and the zone adjustment tube 13 is provided with three ink discharge apertures 20, 21 and 22 which are displaced 90 in relation to each other and which are so placed in the axial direction of the tube that by a turning of the tube they can be made to lie opposite the aperture 16, the aperture 17 or 19 and the aperture 18, respectively, in the ink duct tube in' such a way that by this adjustment there can only be established communication between the ink supply hose and the ink discharge apertures 11 through one of the apertures 16-19 in the ink duct tube 12 and the associated aperture in the zone adjustment tube 13.

As shown in FIGS. 3 and 4, the clearance between the outer tube 10 and the ink duct tube is by means of longitudinal bars, which may e.g. be secured to the ink duct tube 12 by soldering, divided into ink ducts through which from each of the ink discharge apertures 16-19 ink passages are formed to a greater or smaller number of ink discharge apertures 11 in the outer tube 10. More particularly defined, there is between a first generatrix of the tube 12 located opposite the ink discharge apertures 11 and the ink discharge apertures 16, 17 and 18 there is placed a longitudinal bar consisting of a number of bar sections 23, each of which covers two ink discharge apertures 11 and which are separated from each other by spaces 24, while between first said generatrix of the tube 12 and the ink discharge aperture 19 an unbroken, longitudinal bar 25 is mounted. Between the ink discharge aperture 19 and a second generatrix of the tube 12 located diametrically opposite said first generatrix a longitudinal bar is provided consisting of two outer sections 26 and a middle section 27, the clearances 28 between these sections lie halfway between the aperture 19 and one each of the ends of the clearance between the tubes 9 and 12. Between the ink discharge apertures 16-18 and said second generatrix there extends a longitudinal bar with two outer sections 29, two intermediate sections 30 and a central section 31. The four clearances 32 between these sections are located symmetrically in relation to the clearances 28 between the bar sections 26 and the section 27. In the central section 31 there is opposite the ink discharge aperture 17 an aperture 33, and between the section 31 and the section 23 located on the opposite side of the aperture 17 there are on either side of the aperture 17 transverse sections 34 which are constituted by the legs of a U-shaped bar 35 around the aperture 17.

It will appear from this that by of turning of the zone adjustment tube 13 into a position in which there is passage through the ink discharge apertures 16 and 20, the ink will after passing through the aperture 16 flow through the two nearest clearances 24 between bar sections 23 to the four ink discharge apertures 11 located closest to the side wall 1. correspondingly, the ink will by passage through the apertures 18 and 22 flow to the four apertures 11 located closest to the side wall 2. By passage through the apertures 17 and 21 the ink will from the aperture 17 pass through the aperture 33 in the section 31, the clearances 32 between the section 31 and the two intermediate sections 30 and from each of these clearances 32 through the two nearest located clearances 24 between bar sections 23, so that the ink discharge occurs through the eight central ink discharge apertures 11. Finally, the ink will by passage through the ink discharge apertures 19 and 21 pass through the clearances 28 between th sections 27 and the section 26, the clearances 32 between the sections 29, 30 and 31 and the clearances 24 between the sections 23 to the total number of ink discharge apertures 1 1.

By turning of the zone adjustment tube 13, the ink discharge can thus be adjusted to occur in the entire width of the ink cloth in a central section thereof or in one of the two outer sections. After the adjustment of the ink discharge zone desired, ink can be supplied by actuating the push-button 9, whereby the ink pump will be actuated for producing a single ink stroke through the ink supply tube hose 8 and the ink tube 6.

According to the present invention a direct mechanical zone adjustment is obtained by means of a number of operating members equal to the number of different ink discharge zones and each of which operating members is arranged for selectively actuating a coupling between the zone adjustment member and a continuously rotating shaft in the duplicator.

In the duplicator shown in FIG. 1, where, as explained with reference to FIGS. 2-4, it should be possible for example to perform four different zone adjustments, the said operating members have the form of four push-buttons 36, 37, 38 and 39 which together with the above-mentioned push-button 9 are placed in a row at the upper edge of the of the side wall 1. Opposite each of the push-buttons 36-39 the top plate 5 may, as shown, be provided with an indication 40, 41, 42 and 43, respectively, for the corresponding ink discharge zone.

The selectively actuatable coupling between the zone adjustment tube 13 and the said continuously rotating shaft, which for example may be the drive shaft 44 of the-lower drum 3, is as a whole designated by 45 and comprises, as shown in FIG. 2, a coupling disc 46 which is secured on a coupling shaft 47 which by means of a bearing bush 48 is journall-ed in the side wall 1 and in the embodiment'shown is in fixed connection with the zone adjustment tube 13 by means of a connection piece 49. On the coupling shaft 47 a gear wheel 50 is furthermore mounted rotatably, which gear wheel via a transmission consisting of two intermediate gear wheels 51 and 52 mounted on the same shaft engages 1 as shown in FIG. 7, a gear wheel 53 secured on the drive shaft 44, and between said gear wheel 50 and the coupling disc 46, a ball holder 54 is likewise mounted rotatably and is intended for holding a number of balls which in the assembled state of the coupling can be clampedbetween the gear wheel 50 and the coupling disc 46 for establishing a driving connection therebetween.

The coupling 45 is actuatable by means of the pushbuttons 36-39 via actuation arms 55, 56, 57 and 58, re-

spectively, each of which is connected to one of the buttons and which, as shown in FIG. 1, are located side by side in the axial direction of the controllable coupling. At each depression of the corresponding button an arm can be inserted into the path of movement for a stop formed on the outer side of the ball holder, so that the rotation of the ball holder is made to cease by this stop abutting on the particular actuation arm. Thus the coupling between the coupling disc 46' and the gear wheel 50 is released and the gear wheel becomes freely rotatable on the coupling shaft 47.

In FIG. 5. the individual elements of the controllable coupling 45 are shown in an exploded view. The coupling disc 46 consists of a plane circular disc with a tubular bush 59, which is provided with a number of threaded holes 60, in the embodiment shown three such holes, for receiving screws, not shown, for clamping the coupling disc 46 on the shaft 47. The bush on its side facing the gear wheel 50, as shown in FIG. 6, is designed with abutment faces 61, 62 and 63 for balls 64, 65 and 66.which in the mounted state of the coupling are located in bores provided for that purpose in the ball holder 54 and designated by 67, 68 and 69, respectively. Similarly, the gear wheel 50 is provided with a projecting hub portion 70, the side of which facing the coupling disc 46 constitutes a plane abutment face 6 for the opposite sides of the balls 64-66. In the mounted state of the coupling the gear wheel 50 is secured against axial displacement on the coupling shaft 47 by means ofa washer 71 and a locking ring 72 which are mounted in a circumferential recess 73 on the shaft 47.

The above-mentioned stops on the'ball holder 54 consist in the embodiment shown of cams 74, 75, 76 and 77 designed so as to be integral with the ball holder which may be produced of some suitable plastics material, e.g. nylon, which cams are located at mutual angular distances of 90 and with a mutual axial displacement corresponding to the spacing between adjacent actuation arms 5558cconnected to the pushbuttons 3 6-39. Cam 77 on the ballholder is furthermore designed as a securing element for one end of a tension spring 78, the other end of which is secured to the coupling disc 46 in a hole 79 for providing a bias between the coupling disc 46 and the ball holder 54.

Instead of being formed by radially projecting cams. the stops on the ball holder may alternatively have axially displaced grooves which extend in planes at right angles to the coupling axis in the curved surface on part of the circumference of the ballholder and into each of which one of the actuation arms can be inserted by depression of the corresponding push-button. As appears from FIG. 6, the abutment faces 61-63 for the balls 64-66 are inclined under equally large angles relative to the axial direction of the coupling and in a direction so that the axial distance between oppositely located points on one of these inclined abutment faces and plane abutment face of hub portion on gear wheel 50 decreases in the direction of rotation of the coupling shaft when in drive connection with the drive shaft 44. Thereby, the balls 64-66 will, in the assembled state of the coupling, such as shown in FIG. 2, be clamped between the inclined abutment faces 61-63 and the plane abutment face on the gear wheel 50 by means of the bias produced by the tension spring 78. When the coupling 45 is not actuated by depression of one of the push-buttons 36-39, the coupling disc 46 will consequently be coupled to the continuously rotating gear wheel 50 and hereby turn the zone adjustment tube l3 via the shaft 47 and the connection piece 49. When a push-button is depressed, the corresponding cam on the ball holder 54 will abut against the actuation arm connected to the push-button. Thus the coupling disc 46 will be turned in relation to the ball holder against the bias. The balls 64-66 are hereby made to lie opposite the parts of the inclined abutment faces depressed in relation to the plane part of thecoupling disc and are no longer clamped between said faces and the abutment face of the gear wheel 50, so that the gear wheel 50 can turn freely on the shaft 47.

The push-button 36-39 are, as shown in FIG. 1, bi-

ased towards their starting position by means of compression springs 80, 81, 82 and '83, respectively, which are secured at one-end to a common abutment bar 84, which is mounted on the side wall 1, and are connected at the other end to vertically downwardly projecting parts 85, 86, 87 and 88, respectively, of the pushbutton. These parts are connected to the actuation arms 55-58 which from the push-buttons extend downwardly inclined towards the coupling 45. For guiding the actuation of the earns 74-77 of the ball holder 54 by means of the actuation arms the ends of said arms located at the coupling are, as shown in FIG. 7 for the arm 55 at 89, provided with elongated guiding holes for a guiding pin 90 mounted in the side plane 1. Spacing rings 91 corresponding to the desired spacing between the arms are mounted on pin 90 between the individual arms. On the guiding pin 90 there is furthermore pivotably mounted a blocking element 92 with two mounting flanges 93 and 94 located on each side of the arms and an intermediate piece 95. One mounting flange 94 is designed with an elongation for securing a tension spring 96, the other end of which is secured on a pin 97 mounted in the side wall 1, so that the blocking element 92 is biased counter-clockwise for abutment of the intermediate piece 95 against the arms 55-58. Each of the actuation arms is, as shown for the arm 55, provided with two notches 98 and 99 for accommodating the intermediate piece 95 in the depressed position and the starting position, respectively, for the button.

The co-operation between an actuation arm and the coupling 45 is illustrated in greater detail in FIG. 7 for the arm 55 which is shown in dotted lines in its depressed position where the terminal end of the arm shaped with a catch 100 is inserted into the path of movement for the associated cam 74 on the ball holder 54 and thereby prevents rotation of the ball holder, so that the coupling is released. ln this position the intermediate piece 95 on the blocking element 92 is situated in the notch 98. ln the starting position, push-button and actuation arm take up the position shown in solid lines, in which the catch 100 is removed from the coupling and the intermediate piece 95 is situated in the notch 99.

The adjusting mechanism functions in the following way. At the start of the ink cloth, ink is for instance to be supplied in the full width of the duplicator, which takes place by depressing the push-button 36 located opposite the indication 40 corresponding hereto on the top plate 5, whereby the actuation arm 55 connected to the push-button 36 is inserted into the path of movement for the cam 74 on the ball holder 54 in the controllable coupling 45. When subsequently the duplicator is started, a drive connection will exist between the gear wheel 50 and the coupling disc 46 until the cam 74 abuts against the actuation arm 55, at which time the coupling will be released. Hereby the zone adjustment tube 13, which is connected to the coupling shaft 47, of the ink tube 6 is turned until the aperture 21 in the zone adjustment tube 13 lies opposite the aperture 19 in the ink duct tube 12. When the adjustment of the ink tube has been performed, the button 9 may be depressed for actuating the above-mentioned ink pump to produce a single ink stroke through the ink supply hose 8 and the ink tube 6 to the total number of ink discharge apertures 11. If at a later time it is desired to supply ink in only one transverse section of the ink cloth, for instance in an outer section as indicated by the indication 42 on the top plate 5, the pushbutton 38 corresponding hereto is depressed, whereby the actuation arm 57 with the edge located between the notches 98 and 99 forces the pivotable blocking element 92 out of the notch 98 in the already depressed push-button 55 against the bias from the spring 96, whereby the push-button 36 due to the bias from the compression spring 80 is returned to its starting position, so that the actuation arm 55 is removed from the coupling 45 and the coupling disc 46 is again coupled to the gear wheel 50. By the depression of the push-button 38 the actuation arm 57 is, however, guided into the path of movement for the cam 76 on the ball holder 54, so that the rotation of the ball holder is stopped again when the cam 76 abuts against the arm 57, whereby the coupling is again released. The turning of the zone adjustment tube 13 caused by the depression of the push-button 38 is thus limited to an angle corresponding to the angular distance between the cams 74 and 76 of the ball holder 28, that is to say 180. When the new zone adjustment has been performed, a single ink stroke may again be performed in the ink supply tube 6 to the ink discharge apertures 11 in the said outer section by depression of the push-button 9. By the depression of one of the push-buttons 37 or 39 the mode of operation is exactly the same, which means that a depression of the button through actuation of the blocking element 92 causes the return of an already depressed button to its starting position, whereby the gear wheel 50 and the coupling disc 46 are coupled together while at the same time the actuation arm of the particular push-button is guided into the path of movement of the associated cam on the ball holder 54, so that the coupling is again released when this cam abuts on the actuation arm.

In FIG. 8 a modification of the adjusting mechanism in FIG. 1 is shown, in which the special push-button 9 for actuating the ink pump has been omitted. This is achieved by means of an actuation bar 101 which is placed below the row of push-buttons 36-39 and is common to all the push-buttons and which via the actuation mechanism mentioned above, but not shown in detail can actuate the ink pump. The bar 101 is by means ofa member projecting at right angles to the bar and provided with elongated guide slots 103, mounted on pins 104 secured in the side wall 1 and is biased by a spring 105. The other end of the spring is secured to a pin 106 mounted in the side wall 1, against the direction of the depression movement of the buttons 36-39. The push-buttons 36-39 are biased towards their starting position by compression springs two of which are shown 80' and 83' which each at one end abut against the bar 101 and at their other end against an abutment flange, such as shown at 107 with extension 85', 86', 87, and 88' which project are connected vertically down through a guiding slot in the bar 101. Each of the extensions is provided with an actuation pin such as shown at 108, to actuate bar 101 for downward movement. The actuation arm 55-58 for each push-button is connected to a member 85", 86", 87" and 88", respectively, which by means of elongated guiding slots are mounted movably on guide pins which are in fixed connection with the downwardly projecting parts 85-88. If for instance the push-button 39 is depressed, the downwardly projecting part 88 will act on the member 88 by means ofits guiding pins. The actuation arm 58 will be carried along and the catch on the actuation arm 58 will be guided into the path of movement for the cam 78 in the coupling 45, in the way shown in FIG. 7. However, on the last part ofthe movement pin 108 secured on the extension 88' will actuate the common bar 101 to operate the ink pump for producing a single ink stroke.

When subsequently the push-button 39 is released, the extension 88' is led towards the starting position to release bar 101. However, since actuation arm 58 is locked by blocking element 92 such as shown in FIG. 7 the upwards movement of the push-button will be discontinued when abutment flange 107 abuts against the lower edge of member 88, whereby the return movement will be stopped in an intermediate position of the push-button 39.

Consequently, there may with the same zone adjustment be produced an additional ink stroke by an additional depression of the same push-button 39. By the depression of another push-button, the actuation arm 58 on the depressed button 39 will, on the other hand, as was previously the case be released by a pivoting of the blocking element 92, and hereby the spring 83 will via the parts 88' and 88" return the button 39 to its original starting position.

In the mechanism in FIG. 8, ink will consequently be supplied simultaneusly with the depression of any optional push-button and the ink supply may be repeated within the same ink supply zone by a repeated actuation of the same push-button. Moreover, the mechamism in FIG. 8 is so arranged that the ink supply effected-simultaneously with the depression of a pushbutton does not take place until after the zone adjust,- ment member of the ink tube has been brought into the desired position.

In FIG. 9, a longitudinal section is shown of another embodiment of an ink tube for use in a duplicator, where the ink from the ink pump is led through an ink supply hose, not shown, communicating with the ink tube via a connecting branch 107 which is placed centrally on the outer supply 108 of the ink supply, which tube 108, as is the case with the ink tube 6 in the duplicator shown in FIG. 1, is provided with a number of ink discharge apertures 109 in the generatrix facing the lower drum. In the outer tube 108, an inner ink duct tube 110 is mounted co-axially, and the clearance between these tubes is sealed at the ends by means of bushes 111 and 112 which at the same time form bearings for the zone adjustment member of the ink supply unit, the said member being here constituted by a rod 113 which is axially displaceable in the ink duct tube 110 and which by means of guides 114 in connection with the bush 111 is prevented from turning in the tube 1 10.

In the ink duct tube 110 there is provided, in each of two diametrically oppositely located generatrices, which are displaced 90 to either side of the generatrix located opposite the ink discharge apertures 109, four apertures 115-118 and 119-122, respectively, having the same mutual spacing and located two by two symmetrically around the central plane of the tube, so that these apertures are situated pairwise diametrically opposite each other. In the axially displaceable zone adjustment rod 113, a total of five radial bores 123-127 have been provided which have such a size and placing in the axial direction of the rod that by a displacement of the rod they can be made to correspond with the pairs of diametrically opposite apertures in the tube 110 in such a way that the four desired zone adjustments are obtained.

As shown in FIGS. and 11, ink ducts are also, in this embodiment of the ink tube provided in the clearance between tube 108 and 110 by means ofa number of longitudinal bars. On one side of the connecting branch 107 there extends an unbroken bar 128 and on the other side of the branch a bar with a central section 129 and two outer sections 130 which are separated from the central section by spaces 131, which are located symmetrically in relation 'to the branch and halfway between the connecting branch and each end of the ink tube. On one side of the generatrix located opposite the ink discharge apertures 109 and substantially diametrically opposite the bar 128 there extends an unbroken bar 132 and on the other side of the particular generatrix ane substantially diametrically opposite the bar sections 129 and 130 a bar consisting of a row of sections 133 corresponding to the bar sections 23 in the ink duct tube in FIG. 4 and separated by spaces 134. Associated with the unfolded picture of the ink duct tube, FIG. 11 shows at a-d the zone adjustment rod 113 in the four different positions corresponding to the four ink discharge zones desired. It appears from this that of the five radial bores 123-127 in the rod 113, each of the three bores 123, 124 and 125, each of which can be made to correspond with one of the three pairs of oppositely located apertures in the ink duct tube 110, viz. 115, 119; 11 6, 120; and 117, 121, respectively, has a dimension in the axial direction of the rod equai to twice the dimension of each aperture, and the bores 124 and 125 have a distance between centers equal to the distance between the apertures 116 and 117 or 120 and 121, while the distance between the centers of the bores 123 and 124 is equal to the distance between apertures and 116 or 119 and minus the axial length of the apertures 115-122. To the last pair of apertures 118, 122, two bores 126 and 127 are connected, each of which has an axial length corresponding to the axial length of the apertures and the mutual spacing between which is also equal to said axial length, while the distance between the centers of the bores 125 and 126 is equal to the distance between the centers of the bores 124 and 125 minus 1.5 times the length of the apertures.

Thus, in the position of the rod 113 indicated by a there is by means of the bores 123, 124, 125 and 127 provided ink passages through each of the four pairs of diametrically oppositely located apertures 115-122 in the ink duct tube 110. In the position indicated by b the rod is displaced to the right-hand side a distance equal to the axial length of the apertures 115-122, whereby the passage between the apertures 115 and 119 and the passage between the apertures 118 and 122 are blocked, while the passages in the two central pairs of apertures are maintained. In the position indicated by c the rod is displaced a corresponding distance to the lefthand side of the position indicated by a, whereby the passage between the apertures 116 and 120, the passage between the apertures 117 and-121 and the passage between the apertures 118 and 122 are blocked, while the passage between the apertures 115 and 119 is open. Finally, the rod 113 is in the position indicated by d displaced a distance to the right-hand side equal to twice the axial length of the apertures 115-122, whereby the passage between the apertures 118 and 122 is opened by the aid of the bore 126, while the passages between the apertures in the three other pairs are blocked. It will thus be seen that each of the positions of the rod 113 indicated by a-d in the sequence mentioned corresponds to one of the ink discharge zones represented by the indications 40-43 on the top plate 5 in the duplicator 1.

As appears from FIG. 9, the selectively actuatable coupling 45, of which only the coupling shaft is shown at 135, is connected to the zone adjustment rod 113 via a tubular connecting piece 136 which at one end, e.g. by means of screws as shown at 137, is secured on the end of the rod 113. In its opposite end, the connecting piece is provided with an internal guide pin 138 which fits in a circumferential inclined elliptical guiding groove 139 on the coupling shaft 135, the said groove having such an inclination relative to the axis of rotation that the projection of the major axis of the ellipse on to the axis of rotation has a length equal to three times the axial length of the apertures l15-122 in the ink duct tube 110, so that the rod 113 can be displaced between extreme positions with a corresponding spacing by half a revolution of the coupling shaft 135.

The employment of an axially displaceable zone adjustment member entails a slight modification of the ball holder of the controllable coupling, since the said ball holder now, as shown at 140 in FIG. 12, cannot be provided with cams which are evenly distributed along the periphery with a mutual angular spacing of 90, as all of the four possible positions of the rod 113 should be capable of being taken up in the course of half a revolution. Instead, the ball holder 140, which, incidentally, may have the same construction as the ball holder- 54in FIG. 5, is provided with four cams 141-144 which are evenly distributed over 180 of the periphery with a mutual angular spacing of 60. The axial displacement between the cams may be the same as is the case with the ball holder 54 in the embodiment previously described.

From the foregoing it will appear that a sturdy and rapidly responding adjusting mechanism has been provided for the mechanical adjustment of the ink supply zone in a duplicator by the coupling of the zone adjustment member of the ink tube to a continuously rotating shaft when the adjustment is to be altered, and for the automatic release of the coupling in the position desired of the zone adjustment member. The embodiments described in detail must not, however, be regarded as limiting for the invention, since it will be possible to perform numerous modifications of the construction. Thus, it is possible without any difficulties to arrange the adjusting mechanism for a greater number of ink discharge zones than four, which may for example be useful in duplicators with an increased width of the ink cloth. Moreover, it is within the scope of the invention to use the adjusting mechanism in connection with an ink tube having more than one zone adjustment member.

What is claimed is:

1. A stencil duplicator comprising a lower drum and an upper drum mounted rotably in parallel relationship; drive means for said drums including a continuously rotating drive shaft; an endless ink cloth trained around said drums to support a stencil; means for supplying ink to said ink cloth and including an ink tube extending parallel to the lower drum at a short distance therefrom, said ink tube being provided with a number I of ink discharge apertures facing the lower drum; a

zone adjustment member movably arranged in said ink tube to adjust the ink supply through said discharge apertures to any one ofa number of different zones in the transverse direction of said ink cloth; and an adjusting mechanism to position said zone adjustment member for supplying ink in a desired zone; said adjusting mechanism comprising a number of individual operating members equal to the number of ink supply zones and a coupling which is selectively actuatable by each of said operating members to provide a drive connection between said drive shaft and said zone adjustment member and interrupt said drive connection when the zone adjustment member reaches the position corresponding to the ink supply zone associated with said operated member wherein said coupling comprises a coupling shaft connected with said zone adjustment member; a ball holder mounted rotatably on the coupling shaft; a number of balls accomodated in said ball holder; a gear wheel mounted rotatably on said coupling shaft on one side of said ball holder and having a plane abutment face facing said balls; transmission means for connecting said gear wheel with the drive shaft; a coupling disc secured on said coupling shaft on the other side of the ball holder and having a number of abutment faces equal to the number of balls; each of said abutment faces being inclined relative to the axis of the coupling shaft, so that the axial distance between oppositely located points of said abutment face and said plane abutment face of the gear wheel decreases in the direction of rotation of the gear wheel; and means for biasing the ball holder relative to the coupling disc in said direction of rotation to clamp the balls between the inclined abutment faces on the coupling disc and the plane abutment face on the gear wheel, the ball holder being provided on its outer side with a number of stops equal to a number of individual operating members and each operating member comprising an element arranged to be inserted into the path of movement for an associated stop on the ball holder to prevent rotation thereof, whereby rotation of the coupling disc is prevented.

2. A duplicator as claimed in claim 1, wherein the stops of the ball holder have cams located with mutually equal angular spacings on at least part of the circumference of the ball holder and axially displaced relative to each other, and said elements of the operating members have arms located side by side in the axial direction of the coupling shaft with a mutual spacing equal to the mutual axial displacement of said cams.

3. A duplicator as claimed in claim 2, wherein said cams are distributed on the entire circumference of the ball holder with a mutual angular spacing of 360/n, where n is the number of ink supply zones.

4. A duplicator as claimed in claim 2, wherein said cams are distributed on 180 of the circumference of the ball holder with a mutual angular spacing of 180/n, where n is the number of ink supply zones.

5. A stencil duplicator comprising a housing including two sides walls and a top plate; a lower drum and an upper drum mounted rotatably in parallel relationship between said side walls, drive means for said drums including a continuously rotating drive shaft, an endless ink cloth trained around said drium to support a stencil, means for supplying ink to said ink cloth and including an ink tube extending parallel to the lower drum at a short distance therefrom, said ink tube being provided with a number of ink discharge apertures facing the lower drum; a zone adjustment member movably arranged in said ink tube to adjust the ink supply through said discharge apertures to any one of a number of different zones in the transverse direction of said ink cloth and an adjusting mechanism to position said zone adjustment member to a desired ink supply zone, said adjusting mechanism comprising a number of individual operating members in the form of push-buttons equal to the number of ink supply zones, said pushbuttons being arranged side by side in a horizontal row along a side edge of said top plate perpendicular to the axis of the drums and said top plate being provided with 3,804,010 l3 14 an indication opposite each push-button to indicate the connection when the zone adjustment member reaches corresponding ink supply zone; and a coupling selectivedly actuatable by each of said push-buttons to provide a drive connection between said drive shaft and said zone adjustment member and interrupt said drive the position corresponding to the ink supply zone associated with said push-button. 

1. A stencil duplicator comprising a lower drum and an upper drum mounted rotably in parallel relationship; drive means for said drums including a continuously rotating drive shaft; an endless ink cloth trained around said drums to support a stencil; means for supplying ink to said ink cloth and including an ink tube extending parallel to the lower drum at a short distance therefrom, said ink tube being provided with a number of ink discharge apertures facing the lower drum; a zone adjustment member movably arranged in said ink tube to adjust the ink supply through said discharge apertures to any one of a number of different zones in the transverse direction of said ink cloth; and an adjusting mechanism to position said zone adjustment member for supplying ink in a desired zone; said adjusting mechanism comprising a number of individual operating members equal to the number of ink supply zones and a coupling which is selectively actuatable by each of said operating members to provide a drive connection between said drive shaft and said zone adjustment member and interrupt said drive connection when the zone adjustment member reaches the position corresponding to the ink supply zone associated with said operated member wherein said coupling comprises a coupling shaft connected with said zone adjustment member; a ball holder mounted rotatably on the coupling shaft; a number of balls accomodated in said ball holder; a gear wheel mounted rotatably on said coupling shaft on one side of said ball holder and having a plane abutment face facing said balls; transmission means for connecting said gear wheel with the drive shaft; a coupling disc secured on said coupling shaft on the other side of the ball holder and having a number of abuTment faces equal to the number of balls, each of said abutment faces being inclined relative to the axis of the coupling shaft, so that the axial distance between oppositely located points of said abutment face and said plane abutment face of the gear wheel decreases in the direction of rotation of the gear wheel; and means for biasing the ball holder relative to the coupling disc in said direction of rotation to clamp the balls between the inclined abutment faces on the coupling disc and the plane abutment face on the gear wheel, the ball holder being provided on its outer side with a number of stops equal to a number of individual operating members and each operating member comprising an element arranged to be inserted into the path of movement for an associated stop on the ball holder to prevent rotation thereof, whereby rotation of the coupling disc is prevented.
 2. A duplicator as claimed in claim 1, wherein the stops of the ball holder have cams located with mutually equal angular spacings on at least part of the circumference of the ball holder and axially displaced relative to each other, and said elements of the operating members have arms located side by side in the axial direction of the coupling shaft with a mutual spacing equal to the mutual axial displacement of said cams.
 3. A duplicator as claimed in claim 2, wherein said cams are distributed on the entire circumference of the ball holder with a mutual angular spacing of 360*/n, where n is the number of ink supply zones.
 4. A duplicator as claimed in claim 2, wherein said cams are distributed on 180* of the circumference of the ball holder with a mutual angular spacing of 180*/n, where n is the number of ink supply zones.
 5. A stencil duplicator comprising a housing including two sides walls and a top plate; a lower drum and an upper drum mounted rotatably in parallel relationship between said side walls, drive means for said drums including a continuously rotating drive shaft, an endless ink cloth trained around said drium to support a stencil, means for supplying ink to said ink cloth and including an ink tube extending parallel to the lower drum at a short distance therefrom, said ink tube being provided with a number of ink discharge apertures facing the lower drum; a zone adjustment member movably arranged in said ink tube to adjust the ink supply through said discharge apertures to any one of a number of different zones in the transverse direction of said ink cloth and an adjusting mechanism to position said zone adjustment member to a desired ink supply zone, said adjusting mechanism comprising a number of individual operating members in the form of push-buttons equal to the number of ink supply zones, said push-buttons being arranged side by side in a horizontal row along a side edge of said top plate perpendicular to the axis of the drums and said top plate being provided with an indication opposite each push-button to indicate the corresponding ink supply zone; and a coupling selectivedly actuatable by each of said push-buttons to provide a drive connection between said drive shaft and said zone adjustment member and interrupt said drive connection when the zone adjustment member reaches the position corresponding to the ink supply zone associated with said push-button. 